A special committee of Dell's board of directors has determined that both proposals "could reasonably be expected to result in superior proposals," according to a statement. The special committee intends to continue negotiations with both groups, according to the statement from the special committee.

Dell CEO Michael Dell told the committee of his willingness to "explore in good faith the possibility of working with third parties regarding alternative acquisition proposals," according to the statement. Michael Dell had been reported to be willing to include funding in the Silver Lake deal.

At least one of the alternative bidders, Blackstone, meanwhile, had started to explore other CEO candidates if Dell did not want to remain on board with its bid.

"We intend to work diligently with all three potential acquirers to ensure the best possible outcome for Dell shareholders, whichever transaction that may be," said Alex Mandl, chairman of the special committee, in a statement.

The special committee has not determined if either alternative proposal is superior to the Silver Lake deal for $13.65 per share, which was a 37 percent premium over the average price for the 90 days before rumors of the deal started to circulate and the stock rose.

"There can be no assurance that either proposal will ultimately lead to a superior proposal. While negotiations continue, the Special Committee has not changed its recommendation with respect to, and continues to support, the company's pending sale to entities controlled by Michael Dell and Silver Lake Partners," the committee said in the statement.

Blackstone's proposal calls for shareholders to sell their shares for at least $14.25 per share or remain shareholders and receive new shares valued in excess of $14.25 and the company would continue to be publicly traded on Nasdaq, according to the special committee.

"We intend to fund the transaction using a combination of equity and debt financing, in addition to company cash and cash equivalents. We plan to invest equity amounts in excess of those new equity amounts contemplated by the Merger Agreement to facilitate the proposed transaction," wrote Chin Chu, president of Boulder Acquisition Corp., representing the Blackstone bid. "Based on discussions with equity co-investors, certain strategic partners, and debt financing sources, we are highly confident that financing can be arranged, which will include comparable debt sources and structures as the existing deal."

Blackstone's proposal expires at 5:00 p.m. EST on March 28, according to its bid.

Meanwhile, Icahn's proposal calls for an offer of shares from the new ownership group or $15 per share.

Icahn currently owns about $1 billion in Dell stock and also would provide a $2 billion investment ($1 billion from Icahn Enterprises and $1 billion from Carl Icahn and his affiliates) to purchase additional shares. Icahn would also commit an additional $2 billion of cash equity financing for a total of about $5 billion.

Under Icahn's proposal, Icahn and its affiliates would own 24.1 percent of outstanding shares, Southeastern Asset Management would own 16.6 percent of shares and T. Rowe Price would own 9.3 percent of Dell. The remaining public shareholders would then own the remaining 50 percent of the shares of the surviving company, according to Icahn's proposal.

Icahn expects that its proposal would close by July, but the proposal includes no deadline of acceptance.

"We look forward to proceeding with negotiations as promptly as possible and are prepared … to commit the resources to develop a definitive agreement with you. In addition, we look forward to receiving your confirmation that the special committee has concluded that our proposal is or could reasonably be expected to result in, a superior proposal," Carl Icahn wrote in a letter to Dell's board.

In pre-market trading, Dell shares were selling for $14.60, up 46 cents, or 3.3 percent on Monday.